Russian president Vladimir Putin has signed a treaty making Crimea part of his nation, despite the threat of further punitive sanctions by the West.

Mr Putin made a fiercely patriotic address to a joint session of parliament in the Kremlin, punctuated by standing ovations, cheering and tears.

Britain responded by announcing it would suspend all bilateral military cooperation with Russia, while the US warned of further sanctions against Moscow.

The address came as the conflict entered a military stage, with Ukraine permitting its soldiers in Crimea to use weapons to protect their lives following the death of a Ukrainian soldier during an attack on a Crimean base.

During his speech Mr Putin lambasted the West for what he called hypocrisy, saying Western nations had endorsed Kosovo's independence from Serbia but now denied Crimeans the same right.

"You cannot call the same thing black today and white tomorrow," he declared to applause, saying Western partners had "crossed the line" over Ukraine and behaved "irresponsibly".

He said Ukraine's new leaders, in power since the overthrow of pro-Moscow president Viktor Yanukovych last month, included "neo-Nazis, Russophobes and anti-Semites".

In the hearts and minds of people, Crimea has always been and remains an inseparable part of Russia.

Vladimir Putin

Mr Putin said Crimea's disputed referendum vote on Sunday, held under Russian military occupation, was in full accordance with democratic procedures and international law.

He said the results showed the overwhelming will of the people to be reunited with Russia after 60 years as part of the Ukrainian republic.

"People in Crimea clearly and convincingly expressed their will. They want to be with Russia," he said.

To the Russian national anthem, Mr Putin and Crimean leaders signed a treaty that would be ratified within the next few days.

Mr Putin also sought to reassure Ukrainians that Russia did not seek any further division of their country.

Fears have been expressed in Kiev that Russia might move on the Russian-speaking eastern parts of Ukraine.

"Don't believe those who try to frighten you with Russia and who scream that other regions will follow after Crimea," Mr Putin said.

"We do not want a partition of Ukraine. We do not need this."

Ukraine's foreign ministry said it did not recognise the treaty.

"The signing of the so-called agreement on Crimea joining the Russian Federation and the corresponding address by the Russian president has nothing in common with law or democracy or common sense," ministry spokesman Evhen Perebynis said on Twitter.

"Putin's address very clearly demonstrates just how real the threat is that Russia poses to international security."

UK suspends military cooperation, US warns of further sanctions

Russia began seizing the region after Mr Yanukovych was ousted last month, following a violent uprising in which nearly 100 people were killed.

The US and the European Union foreign ministers condemned the move, and labelled the weekend referendum illegal.

On Monday, the United States and the European Union imposed personal sanctions on a handful of officials from Russia and Ukraine accused of involvement in Moscow's military seizure of the Black Sea peninsula.

After Mr Putin's speech, British foreign secretary William Hague announced that all bilateral military cooperation with Russia would be suspended.

"We have suspended all such cooperation," he told parliament, saying a technical cooperation agreement and joint naval exercises with Russia, France, Britain and the US had been put on hold.

German chancellor Angela Merkel said Russia's absorption of Crimea violated international law.

"The so-called referendum breached international law, the declaration of independence which the Russian president accepted yesterday was against international law, and the absorption into the Russian Federation is, in our firm opinion, also against international law," she said.

US vice-president Joe Biden condemned Russia's actions, calling them nothing more than a "land grab" and warning of further sanctions against Moscow.

"Russia's political and economic isolation will only increase if it continues down this path and it will in fact see additional sanctions by the United States and the EU," he said.

The White House said the US and its G7 allies would gather next week at The Hague to consider a further response.

Japan also joined the mild Western sanctions, announcing the suspension of talks with Russia on investment promotion and visa liberalisation.

Russian politicians have dismissed the sanctions as insignificant and a badge of honour.

The State Duma, or lower house, adopted a statement urging Washington and Brussels to extend the visa ban and asset freeze to all its members.

But, echoing comments from Mr Putin, Russia's foreign ministry sharply criticised the sanctions and said it would retaliate.

"Attempts to speak to Russia in the language of force and threaten Russian citizens with sanctions will lead nowhere," it said in a statement.

"The adoption of restrictive measures is not our choice; however, it is clear that the imposition of sanctions against us will not go without an adequate response from the Russian side."

Meanwhile, Ukrainian prime minister Arseniy Yatsenyuk said the conflict with Russia had entered a military stage following the death of a Ukrainian soldier during an attack on a Crimean base.

It is the first such death since Russian forces took control of the region in February.

A Ukrainian military spokesman said the warrant officer was killed by unknown forces who were fully equipped and had their faces covered.

He said another serviceman was injured in the attack and the Ukrainians had their weapons, money and identification confiscated.

Until the incident, Ukrainian forces deployed on the Black Sea peninsula had been told to avoid using weapons.

But a defence ministry order issued after the incident said: "In connection with the death of a Ukrainian serviceman ... Ukrainian troops in Crimea have been allowed to use weapons to defend and protect the lives of Ukrainian servicemen."

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